Unilateral conductor for rectifying alternating currents



Qct. 28, 1930. H G RE 1,780,057

UNILATERAL CONDUCTOR FOR RECTIFYING ALTERNATING CURRENTS Filed Oct. 29, 1926 Patented Oct. 28, 1930 UNITED STATES PATENT OFFICE HENRI G. ANDRE, OF PARIS, FRANCE Application filed October 29, 1926. Serial No. 145,016.

The present invention relates to electrical apparatus and in particular to alternating current rectifiers in which two metals of different character are employed as electrodes,

6 the metals fulfilling alternately the function of cathode and anode. In my application Serial No. 26,748, filed April 29, 1925, entitled Unilateral conductor for rectifying alternating current, duplicated in French Patent 1 30,398, second addition of main Patent 585,955. I have disclosed a unilateral conductor in which one of the electrodes took the shape of a helix or other form of continuous winding, the other electrode comprising a particle mass intercalated between the convolutions of the helix. As comprising part of the unilaterally conducting medium, I preferredto use a layer of a compound of oxidation on one or both electrodes, derived by con- 9 tinual subjection to a strong reactant fluid penetrating the particle mass confined within a receptacle.

The general principles of the invention above stated have also been set forth at length in another application Serial No. 7 49,214, filed by me on November 11, 1924, and entitled Unilateral conductor for rectifying alternating current, a duplicate of which is French Patent 585,955, and the first addition 29,760 thereto.

I have found through practice that the presence of the oxidizing liquid is no longer necessary or even desirable after the film or layerhas been formed. If the oxidizer is an acid, not only is'evaporation and spillage likely to occur,,but in the event of a broken en velope, it may escape and do damage. Having no furtherneed of the acid, it. is obvious that the receptacle may also be dispensed with,tending to reduce the external dimensions of the rectifier.

Accordingly, the primary object of my invention is to devise a rectifier devoid of liquid. .Another. object is to produce astructure capable of passing relatively large amounts of current but is diminutive in size and'rugged. Other features will be apparent a's-the specification is perused.

. j The accompanying drawing illustrates an and placed manually between the turns, as

exemplary embodiment of the device'forn'iing the subject of the present invention. In the figure numeral 1 designates a cylinder or rod of a nickel alloy or other metal, the oxidation products of which aid in furnishing a medium permeable to current in one direction only. About the cylinder is wound a helical member 2 of a metal, as silver, that lends itself readily to colloidal or finely divided form. This member terminates in lead 3. In order to derive the layer on cathode 1, I place the unit in the vicinity of material that produces rapid oxidation as, for example, by immersing in a strong solution of sulfuric acid. While in the acid bath connection is made to an alternating current source to produce electrolysis, which action fractionates a portion of the silver anode into colloidal mass 4, the particles lodging securely between convolutions of the helix, as shown, and filling any space that exists between latter and the cylinder. The process just described has been disclosed and claimed in another of my applications Serial N 0. 138,924, filed October 1, 1926, and entitled Rectifying apparatus.

As soon as the colloid is formed the unit is withdrawn and the excess acid removed either by drying directly with cloth or plunging in water and then drying or even baking, after which the rectifier is ready for operation. \Vhile I have described a method of forming the colloid in place by electrical means, it is obvious that the powdered mass could be derived by apparatus, separate from the unit,

disclosed in my application Serial No. 26,748

supra.

As shown, lead 3 and anode 1 are connected in series with a circuit fed by source 5 of suitable voltage and frequency through stepdown transformer 6 and has for a load apparatus' which requires a relatively large amperage, for example, battery 6 or filaments of a radio receiver. After the passage of some current through the rectifier, the cylindrical member apparently transfers the role of anode to the silver colloid which provides many points of contact and enables the device to pass current of a high order. The oxide layer on the cathode permits current to pass between electrodes in one direction only and, accordingly, directicurrent potential is applied across the load. The particle mass appears to agglomerate slightly, butas far as I have been able to determine causes substantially no impairment of the rectifying property.

\Vhile the unilateral conduction characteristic has been attributed in part to the oxi-d'e film on the cathode, it is apparent that other factors may be involved; for example, on the anode there appears to be a slight deposit of a .sulfide which may aid in the rectifying process. Furthern'iore, continued passage of current would seem to substantially dry out any acid remaining in the pores of the metal, and as far as I am able to ascertain, no further oxidation takes place other than that caused by the atmosphere. However, I do not desire to be limited to any particular theory of operation because the phenomenon is broadly new and further investigation may substantiate a different mode of action. The fact remains that a unit comprising a rod of nickel alloy containing 23% silicon and diameter upon which had been wound twelve turns of 1 1; diameter silver wire when connected to. a supply of commercial voltage and frequency continuously passed a direct currentof one to two amperes at six volts with a loss of only from ORG-llitlfllO one watt.

In View of the foregoing, it is apparent that, if desired. I may enclose either partially or completely the rectifying unit in a casing as a protection from external injury.

I claim 1. In the manufacture of a colloid rectifier having two electrodes separated by a unilaterally conducting medium, a portion of which comprises an oxidation product, the method which consists in placing one electrode about the other, immersing-in a solution to produce the oxidation product on one of the electrodes, passing electrical energy through the rectifier to form a colloid and finally, in removing substantially all excesssolution.

2. In the manufacture of a colloid recti fier having two electrodes separated by a unilaterally conducting medium, a portion of which comprises an oxidation product, the method which consists in winding one electrode about the other to form convolutions, immersing in an oxidizing agent, positioning metal in finely divided form between the convolutions, and drying the rectifier to remove substantially all excess oxidizing agent.

3. In the manufacture of a rectifier unit embodying two electrodes separatedby .a

layer comprising an oxidation product, the

method which consists in subjecting the unit to an oxidizing agent, and after the layer has been formed, removing substantially all 6X- ccss oxidizer from the unit.

4. In the manufacture of a colloid rectifier having two electrodes separated by a unilaterally conducting medium, a portion of which comprises an oxidation product, the method which consists in disposing one electrode about the other to form intercalations therebetween, immersing the entire unit in uid and gas the combination of two spaced electrodes, one of said electrodes being a film forming metal and comprising a cathode, the other of said electrodes having a conducting oxide and substantially solid means in colloidal form derived from said other electrode bridging the space between said electrodes for imparting to the unit a unilaterally conducting characteristic.

6. A rectifier comprising a film forming metallic cathode as a core and another electrode having a conducting oxide wound around said core, said other electrode having formed thereon and'bridging the space between said electrodes,'a substance which results from the immersion of said rectifier i concentratedsulphuric acid.

Signed by me at Boston, Massachusetts, this 17th day of September, 1926.

HENRI G. ANDRE. 

